Electromagnetic sound-producer.



L. GRUBMAN.

ELECTROMAGNETIC SOUND PRODUCER. APPLICATION FILED JUNE 31, 1914.

l,14'?,0;16., Patented July 20, 1915.

WITNESSES." [Ni EN 70/? 1 ATTORNEY KINITED %TATE% LEO GRUBMAN, OF NEWYORK, N. Y., ASSIGNOR TO ELECTRIC SPARK APPLIANCE CO. INC., OF NEW YORK,N. Y., A CORPORATION OF NEW YORK.

ELECTROMAGNETIC SOUND-PRODUCER.

Specification of Letters Patent.

Patented July 20, 1915..

Application filed June 11, 1914. Serial No. 844,401.

To all whom it may concern:

Be it known that I, LE0 GRUBMAN, a citizen of the United States, and aresident of the borough of Brooklyn, county of Kings, city and State ofNew York, have invented certain new and useful Improvements inElectromagnetic Sound-Producers, of which the following is aspecification.

My improvements relate to the class of sound producing devices in whichan elastic resilient diaphragm, or sound-wave vibrator, is actuated byelectro-magnetic means, usually in conjunction with anarmature'interposed between the electro-magnet and said elasticresilient diaphragm, the pulsations of the armature being transmitted tothe said diaphragm through the medium of various instrumentalities. Inall such cases, so far as I am aware, the hammer or armature has beenpositioned between the magnet and the diaphragm, and the diaphragm hasderived its motion from the armature.

In the present case I position the diaphragm between the magnet and thearmature or hammer, and thelatter derives its motion from the diaphragm,this being one of the, distinctive features of the invention.

Another is the provision of means for regulating the tone of thediaphragm by controlling the motion of the armature or hammer, all ashereinafter more fully de scribed and for purposes set forth.

In the accompanying drawings, Figure 1,-

is a rear view of, say, an automobile horn made in accordance with mypresent invention; Fig. 2, a central sectional elevation upon plane ofline 22 Fig. 1; ,F ga sectional detail upon plane of line 33 'Iheconstruction and arrangement of parts shown in the drawings is designedmore particularly for use where an alternating electric current isavailable, as for instance on Ford automobiles, or elsewhere, wheretransformation of current is unnecessary; Thatis to say the usual andwell known make and break means, or

interrupter used in connection with e ectro-magnetic horns supplied withcontinuous electric current 1s omitted, although such device maybe addedwhen necessary without materially altering the construction andarrangement of parts, or the principle 'of action involved herein. Thus,if my present invention is to be embodied in a horn operated by means ofa continuous current of electricity, the interrupter mechanism shown anddescribed in either of my concurrent applications No. 825,114, filedMar. 16th, 1914, or No. 810,431, filed May 23d, 1914:, may be added tothe sound producing mechanism herein disclosed with but slightmodification of either, if any at all,- it being immaterial in so far asmy present invention is concerned, how the alternating current fed tothe coil C, is attained.

The omission of interrupter mechanism of course enables me to simplifyand cheapen the construction of an automobile horn, or similar alarmdevice, very materially, although this is only an incidental feature inconnection with the present invention, one distinctive feature of whichis the interposition of the diaphragm D, between the ele'ctro-magnet M,and the hammer H, and this whether the latter acts as an armature ornot. That is to say, the hammer H, may or may not be formed of magneticmaterial, while the diaphragm D, is formed of magnetic material and isacted upon di rectly by the electro-magnet M. The latter consists bypreference of a circular plate m, formed with an inturned center orhollow core m, an annular spacing block m and a disk m with a centralaperture m, all said parts m, m, m and m being made of magneticmaterial. The electric coil C, is situated between the magnetic platesm, m and surrounds the hollow core m, and it is connected in electriccircuit by means well known and not necessary to show or describeherein. The hollow .core m, extends to and through the central aperturem in the disk m its inturned edge being flush with the rear face of thelatter, as shown in Fig. 2. A spacing washer d, or equivalent, isinterposed between the diaphragm D, and the magnetic plate m and thearmature or hammer carrying spring h, is mounted on a spacing block it,which is by preference made annular so as to form also a bearing orsupport for the bracket 6, upon which the tuning screws t, t, aremouhted. 22 is a nut lock plate for securing the tuning screw t, in apredescr bed position. These parts are all inclosed in a casing A, andheld thereto on one side by anchor screw bolts a, a, passing through thefront plate a, of the casing A, the magnet members m, m m the spacingwasher (Z, the edge of the diaphragm D, the block it, andthe springh,and on the other side by anchor bolts a a passing through the frontplate of the casing, the magnetic members m, m m the spacing washer al,the edge of the diaphragm D, the block it, rise block b, and bracket 1),both sets of screw bolts (1,, a, and 41?, a being secured in place bynuts a a -A horn e, is attached to the frontal member a, of the casingA, opening therethrough into coincidence axially with the hollow core m,of the electro-magnet M, as shown in Fig. 1, so as to receive andtransmit the air pulsations created by the diaphragm in action. Thecasing A, may be left open at the back to be closed by the part to whichthe instrument may be attached, (as by means of the flange (L3,) to thedash board or other fixed part of a Ford machine, to which for itssimplicity, cheapness, and adaptability to a variable alternatingelectric current my device is particularly suited, although applicablefor use generally for alarm or sound warning purposes.

The alternating current is. transmitted to the coils C, through themedium of binding nuts 2', i, and screws 2', i, mounted on the bracketZ2, and insulated therefrom as shown in Fig. 3.

It is well known that it is difficult to construct an automobile hornthat will respond uniformly or satisfactorily to' the varying frequencyof an alternating current not 'produced and regulated by an interrupteror make and break device, but derived for instance from the uncertainand changeable speed of an alternating current auto-magneto, largelybecause the weight of the armature is not mechanically responsive tocurrents of high frequency. Furthermore, as heretofore arranged, thediaphragm has derived its motion from the armature, and the latter,owing to its weight, has not always been responsive to the fluctuationsof an alternating current, especially one of high frequencies. If toobviate this, armatures of very light weight are used theylack therequisite power ofimpact with the diaphragm to insure'volume and tone. Iobviate this difficulty mainly by interposing the elastic resilientmagnetic diaphragm between the electro-magnet and the hammer, which latter need not necessarily be of magnetic material in this arrangement,and hence need not act as an armature. In fact I reverse the order ofarrangement and operation by making the diaphragm impart motion to thehammer. Improvement results from the fact that the diaphragm will alwaysrespond to all frequencies of magnetic attraction, the mechanicalvibration of the diaphragm being assured irrespective of variableelectrical conditions. The vibrations thus positively and directlyproduced in the diaphragm by the magnetic pulsations not necessarilybeing sufficient to afford the requisite loudness or volume of sound,are mainly utilized by me to effect the vibration of the hammer, be thelatter magnetic ornon-magnetic. As a result dynamic power is imparted toand accumulated by the slower moving hammer, which reacts on thediaphragm with suflicient force to intensify, augment, and accentuatethe resultant tone or volume 'of sound. In efiect the hammer thus usedbecomes a tone-strengthening device, or intensifier, incontra=distinction to the old use of the armature as a tone producer per86. When the hammer is magnetic the dynamic energy imparted thereto isaugmented by the magnetic influence, but it still derives its mainimpetus from contacting with the diaphragm. In this connection it may benoted that either the diaphragm D, or the hammer H, (or both) ispreferably provided with a contact protuberance p, as may be preferred,for the purpose of limiting and centralizing the point of contactbetween said parts.

The vibrations of the hammer being relatively slower than those of thediphragm, as above indicated, it is desirable to insure synchronousconcordance of contact and vibration between the two, and for thisreason I furnish the adjustable tuning screw 25, by means of which thescope of vibration of the retractile spring h, may be restricted oramplified as may be found necessary to bring the hammer and diaphragminto average uniformity of accord. The screw 2 is locked in theprescribed position by any suitable means, as by the nut plate 25 andpinching screw t, as will be understood by reference particularly toFig. 2.

It will thus be seen that my invention involves not only anewcombination and arrangement of parts, but a new method of operationalso, 2'. e. the imparting of motion to the hammer through the medium ofthe diaphragm, and the reaction of the hammer against the diaphragm asan intensifier as hereinbefore set forth,the hammer in such case by itsacquired dynamic force and inertia amplifying and accentuating theresultant tone and volume of sound thus produced by the magneticpulsations. The method also of attaining harmonious synchronism betweenthe diaphragm and the heavier and slower moving hammer by regulatlng thearea or scope of vibration .of the latter I also believe to be originalwith myself, and of special value in connection with the use ofalternating electric currents of variable frequency as herein set/forth.

What I claim as my invention and desire to secure by Letters Patent is,

1. In electro-magnetic sound producers of the character designated, incombination,

an electro-magnet, a retractile armature, and an elastic resilientdiaphragm movable independent of said armature and interposed betweensaid magnet and armature, for the purpose described.

2. In electro-magnetic sound producers of the character designated,incombination, an electro-magnet, a retractile hammer, and an elasticresilient diaphragm movable independent of said armature and interposedbetween said magnet and armature, for the purpose described.

3. In electro-magnet sound producers of the character designated, incombination, an electro-magnet, a retractile hammer, an elasticresilient diaphragm positioned between said magnet and said hammer toreceive direct impact from the latter, and means for controlling thetone of the diaphragm by regulating the scope of vibration of thehammer, for the purpose described.

4. In electro-magnetic sound producers of the character designated, incombination, an electro-magnet, a hammer mounted on a flat retractilespring, an elastic resilient diaphragm positioned between said magnetand said hammer to receive direct impact from the latter, and.means forcontrolling the tone of said diaphragm by regulating the scope ofvibration of said hammer and retractile spring, for the purposedescribed.

5. In electro-magnetic sound producers of the character designated, incombination, an electro-magnet, a retractile armature, an elasticresilient diaphragm positioned between said magnet. and said armature,and means for controlling the tone of the diaphragm by regulating thescope of vibration of said retractile armature, for the purposedescribed.

6. In electro-magnetic sound producers of the character designated, incombination, an electro-magnet, an armature mounted on a fiat retractilespring, an elastic resilient diaphragm positioned between said magnetand said armature, and means for controlling the tone of said diaphragmby regulating the scope of vibration of said armature and retractilespring, for the purpose described.

7. In electromagnetic sound producers of the character designated, incombination, an electro-magnet, a hammer mounted on a flat retractilespring, an elastic resilientdiaphragm positioned between saidelectromagnet and said retractile hammer to receive direct impact fromthe latter, and an adjustable screw positioned to limit the scope ofvibration of said retractile spring and hammer, for the purposedescribed.

8. In electro-magnetic sound producers of the character designated, incombination, an electro-magnet, a hammer mountedon a fiat retractilespring, an elastic resilient diaphragm positioned between saidelectromagnet and said retractile hammer to receive direct impact fromthe latter, an adjustable screw positioned to limit the scope ofvibration of said retractile spring and hammer, and means for lockingsaid adjusting screw in a prescribed position.

9. In electro-magnetic sound producers of the character designated, incombination, an electro-magnet, a hammer mounted on a fiat retractilespring, an elastic resilient diaphragm positioned between saidelectromagnet and said retractile hammer, an adjustable screw positionedto limit the scope of vibration of said retractile spring and hammer,means for locking said adjusting screw in a prescribed position,consisting of a lock nut plate and binding screw for clamping said locknut plate, for the purpose set forth.

10. In electromagnetic sound producers of the character designated, anelectro-magnet comprising a magnetic plate formed' with an inturnedcentral hollow core flange, an annular ring of magnetic materialsupported upon said plate, a magnetic disk supported upon said ring andformed with a central opening concentric to said hollow core, and anelectric coilpositioned within the magnet thus constituted andconcentric to the hollow core, in combination with a retractile hammerand an elastic resilient diaphragm positioned between said magnet andhammer to be actuated by said electromagnet, for the purpose described.

11. In electro-magnetic sound producers of the character designated, anelectro-magnet comprising a magnetic plate formed with an inturnedcentral hollow core flange,

an annular spacing ring of magnetic material supported upon said plate,a magnetic disk supported upon said ring and formed with a centralopening concentric to said hollow core and through which the lattereXtends, and an electric coil positioned within the magnet thusconstituted and concentric to the hollow core, and with an elasticresilient diaphragm and an armature positioned to be actuated by saidelectromagnet, said diaphragm being independent of the armature anddisposed'between the latter andthe magnet to receive direct impact ofsaid armature.

12. In electro-magnetic sound producers of the character designated, anelectromagnet comprising a magnetic plateformed with an inturned centralhollow core flange, an annular spacing ring of magnetic materialsupported upon said plate, a magnetic disk supported upon said ring andformed with a central opening concentric to said hollow core and throughwhich they of said armature and interposed between the same and themagnet to receive the direct impact of said armature.

13. In electro-magnetic sound producers of the character designated, anelectro-magnet comprising a magnetic plate formed with an inturnedcentral hollow core flange, an annular spacing ring of magneticmaterial, and a magnetic disk formed with a central opening concentricto the said hollow core, in combination with an elastic resilientdiaphragm positioned upon one side of the electro-magnet and with a hornpositioned upon the other side of said electro-magnet in axial alinementwith, and opening into, the hollow core of said electro-magnet and ahammer upon the side of the diaphragm opposite said electro-magnet forthe purpose described.

LEO GRUBMAN.

Witnesses:

G120. WM. MIATT, DOROTHY MIATT.

